Centering device.



H. MANN.

U'ENTBILING DEVICE.

MPLIUATIUN mmm una. a, w09.

Patented Oct. 8, 1912.

WMM

and the lamp is lighted. H the work is now rotated' and there should be anyirregularity in the surface or in the parallel positioning of the wor with reference to the chuck, the lamp will icker, while, on the other hand, it the surface is perfectly true and the work is parallel to the chuck, the lamp will shine steadily. Y

Vihen it is desired to ascertain Whether or not the work has been placed properly with reference to the. center of the face plate, chuck or other work carrying member, there is mounted a collar 19 on the endof the body portion or casing adjacent to the outer end'of the contact member 12. This collar may be secured imposition by means of the screw 20. Mounted upon this collar is a Small bell crank 2l pivcted at 22 in'the ears 23, one end of said bell crank bearing against the outer end of the contact member. If the centering device is now brought up against the work until the bell crank engages the inner bore or outside circumference of the work, suiiicient to cause the lamp to be lighted, then the rotation of such work, if

not properly centered, will cause the said lamp to flicker, while if the work is perfectly true, the light will remain steady.

The expression centering device has been used throughout this specification and throughout the claims to characterize the invention. This is not intended, however, as an expression of limitation, since, as shown, the function of the device is not always that of centering the work or detecting a displacement of the worlr away from the center, but also to detect the irregularities of surfaces. I

ln order to prevent short circuiting of the current, the movable Contact member is preferably insulated from. the bodyl ofthe tool, This may be accomplished by surrounding said member with an insulating bushingfQfl, the current being led to the movable member by means of a projection on the terniinall?, which engages the sleeve member 30 surrounding the member l0. I ber 13 of the plunger is also provided on its inner end with a point 26 of insulating material for Contact with the head ot the movable electrode. The insulated wires conducting the current to the electrode terminals are preferably placed ina longitudinal bore on the under side of the tool body and which terminates 'at the/ electrode terminals-so that the connections are easily made and the Wires are fully protected and ydo not interfere in any way with placing the tool body on ,the post or in proceeding with the Work.I feature is clearly disclosed in Tkig. 2. Y ,'What is claimed, is: n

LA centering device comprising aA tool body having a longitudinal bore, a plunger slidingly engaged lin the said bore. a signal T he inem? This analogie lamp mounted at the inner end of said bore, the tool body having an opening in the top thereof to expose said signal lamp, and a switch interposed between the inner end of the plunger and the lamp, adapted to be actuated by the said plunger.

2. A centering device comprising a tool body having a longitudinal bore therein, a plunger slidingly engaged iii the said bore, a signal lamp mounted in the tool body at the inner end ot' the bore, the tool body having an opening to expose said signal lamp, and a. switch interposed between the plunger and signal lamp, the said switch having a movable electrode adapted to be engaged by the inner end of the plunger.

3. A centering device comprising a tool body having a longitudinal bore therein, a plunger slidingly'engaged in the said bore and consisting of a contact member having an outer exposed portion for engagement with the work, an inner part, and a spring interposed between the two parts of the plunger, a signal lamp mounted in the tool body at the inner end.' of the bore, the tool body having an opening to e/tlp'vlse said sig nal lamp, and a switch interposed between the plunger and signal lamp, t ie said switch having a. movable electrodMadapted to/ be engaged by the inner part of the plunger.

4. A centering device comprisin a tool. ibodv having a longitudinal bore, plunger slidingly engaged in the said bore, an electric signal mounted at the inner end of the bore, the tool body having an opening in theqo@ able part to be engaged and actuated by the,

plunger, and means for cond'iictingeelectiic current to the said switch.

f 5. A centering device comprising a teolf body having a longitudinal bore, a plunger"` an elecslidingly engaged inthe said bore, triosignal mounted in the tool body at the inner end of the terminal on the under side of the tool body .having connection. with the signal, a movn able electrode interposed atv the inner end of the bore in the tool body between the plunger and the signal, a second rterminal on the under vside oflthe tool body having conneo tion with the movable electrode,the tool body having a passage extending longitudinally through the lower part thereof in line with the terminals aforesaid, and electric conductors extending through said passageto the terminals. c

G. ln a centering device, a tool body, a signal carried by said tool body and having a stationary electrode, a stationary abutment i `member in said tool body, a movable elecelectrode out of contact wit the stationary bore aforesaid, an electric.

electrode, insulation material insulating the the tool body, for conducting current to the 10 abutment member and movable electrode abutment member. l 'irom the tool body, a plunger sldingly Signed at Brooklyn, in the county of 4 mounted in the tool body and adapted to Kings and State of New1 York this 1st day 5 move the movable electrode into contact with of December A. D. 1909.

the stationary electrode, insulation between HARRY M JANN, the plunger and the movable electrode, Witnesses: means for conducting current to the sta- R. SHOPE,

tionary electrode, and means, insulated from FERDINAND GENABD. 

